Measurement of pain

ABSTRACT

The invention relates to a measuring instrument for the measurement of an existing pain or a feeling of nausea of a patient. The measuring instrument induces pain in an arbitrary body part of said patient, by supplying an electrical current. The measuring instrument provides a current increase into said body part, until said induced pain is experienced by the patient as being as great as the existing pain/nausea. The current is supplied from a current source arranged in the measuring instrument via wires (H, I) and electrodes (C, D), said electrodes being applied onto that part of the body in which pain is to be induced. When the pain induced is experienced to be as great as the existing pain/nausea, the body part is removed from the electrodes, whereupon a pain value is registered and shown on a display (F). (FIG.  6 ).

AREA OF THE INVENTION

[0001] The present invention relates to a measuring instrument and amethod of measuring, by means of said instrument, an existing painexperienced by a patient.

STATE OF THE ART

[0002] When a person in need of medical treatment first comes intocontact with a doctor, a physiotherapist, a nurse etc., this persongenerally tries to describe his pain verbally, so that the medical staffare at least able to make a primary diagnosis of the patient's conditionand suggest a suitable treatment. However, this creates a significantproblem for the medical staff, depending upon different personsexperiencing, and therefore describing, their pain or symptoms indifferent ways. One person may e.g. be more resistant to pain thanothers. Another person may e.g. have become used to his pain after acertain period of time and may therefore describe his/her pain in milderterms than he/she would have done if the pain had arisen recently. Thevarying descriptions of pain which a diagnostician may be exposed to,complicate a quick and exact diagnosis of a person's ailment or injury.

[0003] For the sake of simplicity, in the below text the patient isalways referred to as being male. It should of course be understood,however, that the same applies to female patients.

[0004] In order to hitherto measure pain in patients, doctors,physiotherapists etc. use a so called measuring rod or ruler; thistechnique is called Visual Analogue Scale (VAS). The general design of ameasuring rod having a VAS scale is shown in FIGS. 1 and 2. There is,however, a variety of different designs of this measuring rod, but theirfunction is generally the same and will be described with reference toFIGS. 1 and 2.

[0005] As can be seen from FIG. 1, the measuring rod is divided intogrades from e.g. 0-10, where “0” means no sensation of pain and where“10” means unbearable sensation of pain or worst possible sensation ofpain. FIG. 2 shows the reverse side of the measuring rod of FIG. 1, andduring a measurement the patient will only see this side.

[0006] Suppose a patient having a pain in his arm goes e.g. to a doctor.The doctor picks up his ruler (measuring rod) and asks the patient if hecan describe his sensation of pain by placing his finger on that spot onthe ruler which best corresponds to the sensation of pain in his arm.The doctor has of course previously explained to the patient how theruler functions, i.e. that one end A of the ruler corresponds to nosensation of pain and the other end B of the ruler corresponds to anunbearable sensation of pain (FIG. 2).

[0007] Assume that the patient places his finger on the ruler at a valueof “7” on the pain scale (0-10). The scale on the ruler is turnedtowards the doctor so that only he can see the pain scale (FIG. 1) andthe patient can only see the reverse side of the ruler as shown by FIG.2.

[0008] The doctor thus quickly obtains information about how the patientat present subjectively experiences the pain in his arm.

[0009] The doctor then prescribes a treatment for the patient, e.g. somekind of painkiller.

[0010] When the patient comes for his next visit to the doctor, the sameprocedure with the ruler is repeated, and the patient now places hisfinger at a location on the ruler which e.g. corresponds to the value“2” on the pain scale (0-10).

[0011] The doctor thus obtains an indication that the pain in the armhas decreased; the doctor of course comparing the previous value of “7”with the present value of “2”. Thus, the doctor can conclude that thetreatment has been effective.

[0012] If the patient during his next visit instead places his finger ata location on the ruler which e.g. corresponds to the pain value of“8,5”, the doctor can instead determine that the previous treatment hasbeen ineffective, and he can therefore act accordingly; e.g. prescribe anew medicine or a referral to a physiotherapist, a masseur etc. Thedoctor thus uses the measuring rod to determine whether a treatment hasbeen effective or not.

[0013] One problem with this ruler according to FIGS. 1 and 2 is thatthe patient must consciously think about and evaluate where to place hisfinger on the ruler, between the values no sensation of pain andunbearable sensation of pain, as shown in FIG. 2. The patient is all thetime aware of, that the closer he places his finger in relation to theend A of the ruler, i.e. no sensation of pain, the less pain he issupposed to sense, and the closer he places his finger in relation tothe end B of the ruler, i.e. unbearable sensation of pain, the more painhe is supposed to sense. This awareness of the patient is just what thepresent invention eliminates.

[0014] Another problem with the ruler according to FIGS. 1 and 2 is thatthe doctor cannot objectively verify the pain value given by thepatient; the patient may e.g. lie about his sensation of pain and placehis finger at the same pain value at different measurement occasions.

[0015] A further problem with the ruler according to the FIGS. 1 and 2is that different persons sense pain in different ways.

[0016] Some persons can stand pain better than others and will describetheir pain with a low value (e.g. “2”) on the ruler; other persons havea low pain threshold and will describe the same pain with a high value(e.g. “9”) on the ruler.

[0017] The present invention eliminates also this problem.

[0018] In order to find out if the previous art solves the problemsmentioned above, a pre-study was performed, whereby the followingdocuments were found.

[0019] The document EP,B1 0 438 541 describes a portable instrumentperforming a multidimensional indication of pain sensed by a person. Theportable instrument has indicators that may be adjusted by a person toprovide a physical indication of the type of pain intensity being sensedby said person.

[0020] The document U.S. Pat. No. 4,641,661 describes an electronicmeter for determining the pain threshold for a pressure applied to theskin surface of a patient. The pressure is increased until the patientpresses a button when he/she senses pain. The pressure achieved isregistered.

[0021] The document U.S. Pat. No. 4,697,599 describes a device forlocalisation and detection of pain by measurement of the conductivity ofthe tissue.

[0022] The document U.S. Pat. No. 5,020,542 shows a method for measuringthe sensibility of the skin of a patient to electrical stimulation.

[0023] The document JP,7 023 964 describes a method for measuring painobjectively and quantitatively.

[0024] The document GB,2 049 431 describes a so called measuring rod forproviding a subjective measurement of the pain sensed by the patient.

[0025] The documents found do not solve the problems mentioned above.

SUMMARY OF THE INVENTION

[0026] Thus, the object of the present invention is to solve the aboveproblems.

[0027] Another object of the present invention is to allow an objectiveway of performing the pain measurement.

[0028] Yet another object of the present invention is to provide ameasurement value of pain which is relevant for comparison betweendifferent patients.

[0029] A further object of the present invention is to provide aportable, very easy to use, measuring instrument for the measurement ofpain.

[0030] Yet a further object of the present invention is to allow thedoctor, the physiotherapist etc. to feel and sense the patient's pain,which has a psychological significance that may entail a shortened timefor medical care of the patient, as the patient feels he has beenunderstood.

[0031] These objects are achieved by a device and a method according tothe characterising parts of the appended patent claims 1 and 16,respectively.

[0032] Advantageous embodiments of the present invention are describedin the dependent claims.

[0033] Detailed embodiments of the present invention will now bedescribed with reference to the enclosed drawings.

SHORT DESCRIPTION OF THE DRAWINGS

[0034]FIG. 1 shows a principle design of a measuring rod (ruler)according to the state of the art, seen from the front;

[0035]FIG. 2 shows the measuring rod of FIG. 1 seen from the rear;

[0036]FIG. 3 shows a cross sectional view from above of a firstembodiment of the measuring instrument according to the invention;

[0037]FIG. 4 shows a side view of the measuring instrument of FIG. 3;

[0038]FIG. 5 shows a second embodiment of the measuring instrumentaccording to the invention;

[0039]FIG. 6 shows a cross sectional view from above of a thirdembodiment of the measuring instrument according to the invention;

[0040]FIG. 7 shows a side view of the measuring instrument of FIG. 6;

[0041]FIG. 8 shows a cross sectional view from above of a fourthembodiment of the measuring instrument according to the invention;

[0042]FIG. 9 shows a fifth embodiment of the measuring instrumentaccording to the invention; and

[0043]FIG. 10 shows a cross sectional view from above of a sixthembodiment of the measuring instrument according to the invention;

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0044] In the following, each of the embodiments mentioned according toFIGS. 3-10 will be discussed. The first embodiment of the invention willbe described in more detail, as this embodiment will also describe theidea of the invention by means of an example.

[0045] The other embodiments are based on the same inventive idea.

[0046] Referring now to FIGS. 3 and 4, two electrodes C and D areattached, one on each side, at one end of the measuring instrument. Theelectrodes are connected by wires I and H to a current source, where thecurrent is controlled by a control knob E.

[0047] At one side of the measuring instrument there is a display F,capable of showing, e.g. digitally, a value of e.g. 0-10. This value isof course intended for indication, in the same way as before, of adegree of pain sensed, where the value “0” corresponds to a totalabsence of pain and the value “10” corresponds to an unbearable pain.

[0048] Furthermore, there is a memory register G for storage of anarbitrary number of pain readings (0-10).

[0049] The present invention will now be described by way of an example,with reference to FIGS. 3 and 4.

[0050] Assume that a patient having pains in his arm comes to a doctor.The doctor produces his measuring instrument according to the firstembodiment, and asks the patient to take a steady grip with e.g. hisindex finger and thumb around the electrodes C and D.

[0051] The doctor now informs the patient that a current will besupplied to the electrodes, the increase of which will be controlled bythe doctor via the control knob E. The doctor further informs thepatient that he will sense a pain in the index finger and thumb that aregrasping the electrodes C and D; as the current increases, the pain inthe fingers will increase accordingly. The doctor now informs thepatient that he should release the grip around the electrodes C and Dwhen the pain in his fingers is experienced to be as great as the painin the bad arm.

[0052] The doctor thus increases the current through the wires H and Iwith the control knob E, and when the patient senses that the pain inhis fingers is as great as the pain in the bad arm he releases his griparound the electrodes C and D, whereupon a pain reading, e.g. “7,8” isregistered in the memory G and is displayed digitally on the display F.This pain value is of course proportional to the magnitude of thecurrent.

[0053] When the patient returns after treatment, the same procedure isrepeated, whereupon the pain reading “2” is registered. Thus, the doctornow knows, in the same manner as before, that the treatment has beeneffective.

[0054] The above described measuring instrument according to the presentinvention however differs markedly from the earlier measuring rodaccording to FIGS. 1 and 2, through the patient associating, by means ofthe measuring instrument according to the present invention, a pain (inhis fingers) with another pain (in his bad arm).

[0055] The patient thus releases the grip around the electrodes C and Dwhen the pain in his fingers is experienced as being as great as thepain in his arm, and the patient thus has no idea about which painreading on the scale (0-10) he causes.

[0056] When the patient uses the measuring instrument according to thepresent invention, he will not refer to any greatest (unbearablesensation of pain) or smallest (no sensation of pain) pain value as withthe measuring rod according to FIGS. 1 and 2.

[0057] The pain measurement according to the present invention is thusobjective in the sense that the patient cannot consciously determinewhat pain value he will obtain, as it is the comparison between the painin his fingers and the pain in his arm that is his reference, not anyvisual pain scale.

[0058] Furthermore, as a given pain value corresponds to a given currentlevel, pain values between different patients can be compared. It isthus possible, based on the pain values, to determine objectively that acertain patient will endure greater pain than another patient; this ise.g. not possible with the measuring rod according to FIGS. 1 and 2.With the measuring instrument according to the present invention thedoctor can easily check if the patient is “lying” about his pain byperforming an arbitrary number of measurements and comparing the painvalues from the different measurements; if approximately the same painvalue is obtained throughout all measurements it can be regarded asreasonable that the patient speaks the truth.

[0059] The doctor can also experience the pain which the patient senses,by grasping himself around the electrodes C and D; this may be ofpsychological importance to the patient and entail a shortening of histime in medical care.

[0060]FIG. 5 shows a second embodiment of the measuring instrumentaccording to the invention. This embodiment differs from the measuringinstrument in FIGS. 3 and 4 only by the current to the electrodes C andD being increased by means of a push-button J.

[0061] By depressing this button J, the current is thus increased in anarbitrary, predetermined fashion; for example 50 μA upon eachdepression.

[0062] The FIGS. 6 and 7 show an especially preferred embodiment of themeasuring instrument. This embodiment functions in such a way that whene.g. the thumb and the index finger grasp around the electrodes C and D,a current circuit is closed, whereby a current flows from the currentsource via the wire H and the electrode C through the thumb and theindex finger, and back to the current source via the electrode D and thewire I. The current increases automatically by steps of e.g. 50 μA,being controlled by a microprocessor K. Furthermore, the microprocessormay be programmed so as to control the current increase in a linear orexponential manner. The microprocessor also controls the time it willtake for the current to increase from a minimum current to a maximumcurrent.

[0063] When the current has increased to such an extent that the patientexperiences the pain in his thumb and index finger to be as great as thepain in e.g. his bad arm, the patient releases his grip around theelectrodes C and D, whereupon the current circuit is interrupted, andthe current value is registered, in the same manner as before, in thememory G and shown on the display F. This measuring instrument accordingto FIGS. 6 and 7 is thus very easy to handle and user friendly, as itonly needs for the patient to grasp with his thumb and index fingeraround the electrodes C and D, whereupon the current increase takesplace fully automatically. The measuring instrument according to FIGS. 6and 7 may also be equipped with a stop button (not shown) for stoppingthe automatic current increase. When the patient depresses this stopbutton, the automatic current increase will stop, causing the currentsource only to feed a constant current, corresponding to the currentflowing immediately before the stop button was depressed.

[0064] This stop button may be used, for example, when the doctor wantsto experience the current strength that the patient senses. This is thusperformed through the patient stopping the current increase when theexisting pain (e.g. his bad arm) is experienced as being as great as thepain caused by the current, by depressing the stop button, whereupon thedoctor grasps, with his fingers, around the electrodes C and D. It may,as mentioned before, have a certain psychological impact, that thedoctor can experience the patient's pain, as the patient may then feelunderstood. If the stop button is depressed again, the current willresume its automatic increase.

[0065]FIG. 8 shows a fourth embodiment of the measuring instrument. Thismeasuring instrument in principle functions in the same manner as themeasuring instrument of FIGS. 6 and 7; the current will increaseautomatically when the current circuit is closed (i.e. when theelectrodes C and D are short-circuited).

[0066] This measuring instrument however differs from the earlierdescribed measuring instruments by having its electrodes C and Darranged in such a manner as to be applicable anywhere on the body. Thismeasuring instrument is especially advantageous for use with extremitieswhich are paired, e.g. arms, legs, ears, etc.

[0067] Assume for example that a patient has a pain in his left knee.The doctor then applies the electrodes C and D of the measuringinstrument according to FIG. 8 onto the patient's right knee, whereuponpain is also induced in this knee. The measuring instrument according toFIG. 8 thus utilises the principle that it is easier for a patient toassociate a pain in his left knee with a pain in his right knee; it iseasier to compare pain sensations in similar body parts. The sensationof pain in each side of the body is transferred independently to thebrain. Consequently, the sensitivity in a certain area of the body canbe compared to that in a reference area on the opposite side thereof.

[0068] In the embodiments of the measuring instrument according to thepresent invention, it should be understood that it is also possible toreduce the current via the push-button J or the control knob E. In oneembodiment of the present invention it will be possible to combine theautomatic current increase and the stop button with the push-button J orthe control knob E.

[0069] It will also be possible for a patient to perform the painmeasurement himself, in the absence of a doctor, physiotherapist, etc.In this case, the pain values are not shown on the display F but areonly stored in the memory G, so as not to inform the patient about them.The doctor may subsequently, by means of a certain button (not shown)retrieve these values from the memory G and show them on the displaymeans.

[0070] The memory G will be designed so that arbitrary information, suchas e.g. time, date, various patient names with their respective seriesof pain values etc., may be stored. There will also be a possibility forprinting out this information on e.g. a strip of paper.

[0071]FIG. 9 shows an especially preferred embodiment of the measuringinstrument which is a combination of the measuring instrument of FIGS. 6and 7 and the measuring instrument of FIG. 8. This measuring instrumentis thus designed on the one hand to be grasped around the electrodes Land M with the fingers, on the other to be applicable onto an arbitrarybody part via the electrodes N and O, in the same way as describedbefore.

[0072] In order for the patient to receive adequate pain stimulation inthe body part which is touched by the electrodes, it is necessary tosecure a predetermined minimum pressure against the electrodes.

[0073] One way of achieving this is to see to it that this predeterminedminimum pressure corresponds to the force required to grasp theelectrodes C and D by the thumb and index finger and at the same time tohold the measuring instrument in a horizontal position. In this case itwill be required that a string is attached to an arbitrary position onthe measuring instrument, whereby e.g. the doctor holds the other end ofthe string, to prevent the instrument from falling to the floor when thepatient releases the electrodes C and D. If the doctor is increasing ordecreasing the electrode current manually, in this case, when themeasuring instrument is in a horizontal position, an external hand-heldcontrol is required. The hand-held control is then connected to themeasuring instrument by a wire and thus replaces the push-button J andthe control knob E. If the current increase is automatic, naturally noexternal hand-held control is necessary.

[0074] Yet another method for arranging this predetermined minimumpressure on the electrodes is to use a resilient contact as shown inFIG. 10. In this case, the electrodes must be pressed inwards until theytouch the contacts P and Q, whereby the current circuit is closed. Thispressure for closing the circuit is consequently so matched as toachieve an adequate pain stimulation.

[0075] It should be understood that the measuring instrument accordingto the embodiments described above is a portable instrument that caneasily be carried by e.g. a doctor. The length of the instrument willprincipally correspond to the length of the previous measuring rod.However, the instrument will be somewhat thicker than the previousmeasuring rod, as this instrument has to contain a certain amount ofelectronics.

[0076] The measuring instrument preferably comprises at least a battery,a means of upwards transformation of voltage, a microprocessor fordisplay control etc., and possibly memory circuits. The pain scale to beutilised preferably runs from 0,0-9,9, 0-60 or 0-99.

[0077] It has been shown, empirically, that the pain measurements withthis measuring instrument functions in a very satisfactory way when thefollowing measurement method is used:

[0078] the patient grasps around the electrodes (C, D) with his rightthumb and index finger;

[0079] the current is increased automatically when the circuit is closed(alternatively, the patient has to press the start button in order tostart the automatic current increase);

[0080] when the pain in his fingers is experienced as being as great ashis existing pain in e.g. a knee, the patient depresses the stop button.The automatic current increase ceases and the stimulation remainsconstant. The patient will at this point try “once extra”, that the painin his fingers is as great as the existing pain;

[0081] the patient then releases his tweezers grip around the electrodes(C, D). If the patient thinks the pain in his fingers is lower than theexisting pain, he may push the stop button again, making the currentincrease automatically, etc. It is thus not until the patient releaseshis tweezers grip (open circuit), that the measurement is terminated;

[0082] the doctor depresses the value button, the pain value is shown onthe LCD, and the pain value is noted down.

[0083] It is to be understood that the stop button is arranged at such alocation on the measuring instrument as to be easily accessible for thepatient.

[0084] It is further foreseen that the measuring instrument (the painmeter) will be used for pain measurements outside the hospital. A largeapplication area is pain measurement during studies of pharmaceuticaldrugs. The pain meter must then follow the patient 24 hours/day.

[0085] The patient will perform the pain measurement himself asdescribed above, with the difference that upon a finished measurement,the pain value is saved in a memory and the pain meter is switched offautomatically. The patient consequently will not see the measured painvalue. After e.g. four weeks the patient goes to see his doctor. Thedoctor takes the pain meter and connects it to a computer, preferablyvia an interface. The saved pain values are transferred to the computerfor further analysis/processing. Examples of data saved are patientname/birth data, date (each measurement), time (each measurement), andpain value (each measurement). It is also conceivable that the painmeter includes a system for making the patient aware of that it is timeto perform a measurement, or that the pain meter is integrated into asystem where this function is available.

[0086] In the foregoing, we have only discussed a comparison between aninduced pain and an existing pain. It is of course to be understood,that the measuring instrument according to the invention may be used tocompare an induced pain with, in general, an arbitrary feeling. If, forexample, a patient feels ill at ease, this feeling may be compared witha pain induced into the patient by means of the measuring instrument.The invention is especially intended for also allowing the comparisonbetween a pain induced by the measuring instrument and sensations ofnausea. It is to be understood that in the concept of pain, we alsoinclude unpleasant sensations.

[0087] The quintessence of the present invention, however, is that thepatient receives a physical stimulus (electrical current) into a part ofhis body, and compares said induced pain in this body part with anexisting pain (e.g. his bad arm) or with a feeling of nausea. When theinduced pain in the body part coincides with the existing pain/nauseasensation, the pain value is registered through the patient activelycausing the induced pain to cease.

[0088] In this way the pain may be objectively graded, with the physicalstimulus (the current) as reference, i.e. there is no reference to anyfixed values running from “no sensation of pain” to “worst possiblesensation of pain”.

[0089] It is to be understood that the physical stimulus does notnecessarily have to be an electrical current; it could also be amechanical pressure or application of heat.

[0090] The above description is only to be regarded as advantageousembodiments of the invention, and the scope of the invention is onlydefined by the contents of the accompanying patent claims.

1. Measuring instrument for measuring the existing pain in an arbitrarypart of the body of a patient, or the nausea of a patient, characterisedin that it induces pain into said patient by supplying a physicalstimulus, and in that it provides an increase in said physical stimulusuntil said induced pain is experienced, by said patient, to be as greatas said existing pain/nausea.
 2. Measuring instrument according to claim1 , characterised in that when said induced pain is experienced to be asgreat as said existing pain/nausea, said patient causes said inducedpain to cease, whereby said measuring instrument will register a painvalue corresponding to said existing pain.
 3. Measuring instrumentaccording to claim 2 , characterised in that said physical stimulus isan electrical current.
 4. Measuring instrument according to claim 3 ,characterised in that it is portable and comprises electrodes (C, D),wiring (H, I), a current source, a display means (F) and memory circuits(G), the electrodes being arranged for application onto an arbitrarypart of the body of said patient, for delivery of electrical current. 5.Measuring instrument according to claim 3 , characterized in that it isportable and comprises electrodes (C, D), wiring (H, I), a currentsource and memory circuits (G), the electrodes being arranged forapplication onto an arbitrary part of the body of said patient, fordelivery of electrical current, whereby pain values are registered insaid memory circuits (G), said pain values being transferable to acomputer for analysis/processing through said measuring instrument beingconnected to said computer, preferably via an interface.
 6. Measuringinstrument according to claims 4 or 5, characterised in that saidcurrent increases successively and induces pain in said body part of thepatient, whereby, when said induced pain is experienced to be as greatas said existing pain/nausea, said body part is removed from saidelectrodes (C, D) and said current is interrupted, whereby a pain valueis registered in memory circuits (G) and displayed on said display means(F), if such a device is provided on said measuring instrument. 7.Measuring instrument according to claims 5 or 6, characterised in thatsaid electrodes (C, D) are provided at one end, and on opposite sides,of said measuring instrument, to be grasped preferably by the fingers.8. Measuring instrument according to claims 5 or 6, characterised inthat said electrodes (C, D) are provided closely beside each other atone end, and on the same side, of said measuring instrument, forapplication onto an arbitrary part of the body of said patient. 9.Measuring instrument according to claims 5 or 6, characterised in thatelectrodes (L, M) are provided at one end, and on opposite sides, ofsaid measuring instrument, to be grasped preferably by the fingers, andthat electrodes (N, O) are provided closely beside each other at oneend, and on the same side, of said measuring instrument, for applicationonto an arbitrary part of the body of said patient.
 10. Measuringinstrument according to any one of claims 4-9, characterized in that ithas a resilient contact between said electrodes (C, D, M, L, N, O) andcontacts (P, Q), a predetermined minimum pressure against saidelectrodes being required to press them inwards against said contacts(P, Q), whereby current is supplied to said electrodes.
 11. Measuringinstrument according to any one of claims 7-10, characterised in thatthe current is increased automatically when the electrodes (C, D, M, L,N, O) are short-circuited.
 12. Measuring instrument according to any oneof claims 7-10, characterised in that the current increase is controlledby a control knob (E).
 13. Measuring instrument according to any one ofclaims 7-10, characterised in that the current increase is controlled bya push-button (J).
 14. Measuring instrument according to any one ofclaims 4-13, characterised in that a stop button is provided to stop thecurrent increase when said button is depressed, whereby, if said buttonis depressed anew, the current will resume its automatic increase. 15.Measuring instrument according to any one of claims 11-14, characterisedin that it comprises a battery means, means for upwards transformationof voltage, a microprocessor for control of the display means, memorycircuits, etc.
 16. Method for measuring, by means of a measuringinstrument, the existing pain in an arbitrary part of the body of apatient, or the nausea of a patient, characterised in that pain isinduced into said patient by supplying a physical stimulus to saidpatient by means of said measuring instrument, and in that said physicalstimulus is increased by said measuring instrument until said inducedpain is experienced, by the patient, to be as great as said existingpain/nausea.
 17. Method according to claim 16 , characterised in thatsaid patient causes said induced pain to cease when said induced pain isexperienced to be as great as said existing pain/nausea, whereupon apain value corresponding to said existing pain/nausea is registered. 18.Method according to claim 17 , characterised in that said physicalstimulus is an electrical current.
 19. Method according to claim 18 ,characterised in that said measuring instrument used is portable andcomprises electrodes (C, D), wiring (H, I), a current source, a displaymeans (F) and memory circuits (G), said electrodes being applied ontothat part of the body in which pain is to be induced.
 20. Methodaccording to claim 19 , characterised in that said electrical current issuccessively increased and induces a successively increasing pain insaid body part of the patient, whereby, when said current, inducing painin said body part, has increased to an extent where said induced pain isexperienced by the patient to be as great as said existing pain/nausea,said body part is removed from said electrodes (C, D) whereupon thecurrent is interrupted and said pain value is registered in said memorycircuits (G) and are displayed on said display means (F).
 21. Methodaccording to claim 20 , characterised in that said electrodes (C, D) areprovided at one end, and on opposite sides, of said measuringinstrument, to be grasped preferably by the thumb and index finger. 22.Method according to claim 20 , characterised in that said electrodes (C,D) are provided closely beside each other at one end, and on the sameside, of said measuring instrument, for application onto an arbitrarypart of the body of said patient.
 23. Method according to any one ofclaims 21 or 22, characterised in that the current increasesautomatically when the electrodes (C, D) are short-circuited by saidarbitrary body part.
 24. Method according to claim 23 , characterised inthat a patient with an existing pain, e.g. a bad knee, or beingnauseous, grasps around the electrodes (C, D) with his thumb and indexfinger, whereby said current flows from the current source via the wire(H) and the electrode (C) through the thumb and index finger and back tothe current source via the electrode (D) and the wire (I), said currentincrease thereby occurring automatically, preferably in steps of 50 μA,by means of a microprocessor (K), and when the pain induced by thecurrent in the index finger and thumb, respectively, is experienced bythe patient as being as great as the existing pain/nausea, the patientremoves his index finger and thumb from the electrode, whereby thecurrent circuit is interrupted and a pain value corresponding to theexisting pain/nausea is displayed on said display means (F).
 25. Methodaccording to any one of claims 21 or 22, characterised in that thecurrent increase is controlled by a push-button (J).
 26. Methodaccording to any one of claims 16-25, characterised in that said painvalue may assume values on a pain scale from 0-10, 0-60 or 0-99. 27.Method according to any one of claims 23-25, characterised in that itcomprises the following steps: a) the patient grasps around theelectrodes (C, D) with the thumb and index finger of one hand; b) thecurrent is increased automatically when a closed circuit is created, orthe patient depresses a start button to start the automatic currentincrease; c) when the pain in the fingers (thumb, index finger) isexperienced as being as great as the existing pain in an arbitrary bodypart, or a feeling of nausea, said patient depresses a stop button,whereupon the automatic current increase ceases and the stimulationremains constant. d) the patient checks once again that the pain in thefingers is as great as said existing pain/nausea; e) if the patientthinks the pain in his fingers is lower than said existing pain, hepushes the stop button again, making the current increase again. f) whenthe patient is sure about the pain in his fingers coinciding with saidexisting pain/nausea, he releases the grip around the electrodes (C, D)whereby the measurement is terminated.
 28. Method according to claim 27, characterised in that when the measurement is terminated, a doctordepresses a value button, whereby the pain value is shown on a display(F), whereupon the doctor makes a note of the pain value.
 29. Methodaccording to claim 27 , characterised in that the patient performs thepain measurement himself, preferably at home, whereby, when themeasurement is terminated, the measured pain value is stored in memorycircuits (G) in such a way that the patient will not be informed aboutsaid pain value, whereupon consecutive measurements are performed by thepatient during an arbitrary period of time during which said measuredpain values are stored in said memory circuits (G); and in that when thepatient, after an arbitrary period of time, returns to the doctor, hewill give the measuring instrument to said doctor, who connects themeasuring instrument to a computer, preferably via an interface, wherebysaid pain values are transferred to said computer foranalysis/processing.